Systems and methods for direct current nerve conduction block

Abstract

Disclosed herein are systems and methods for nerve conduction block. The systems and methods can utilize at least one renewable electrode. The methods can include delivering a first direct current with a first polarity to an electrode proximate nervous tissue sufficient to block conduction in the nervous tissue. Delivering the first direct current can place the nervous tissue in a hypersuppressed state at least partially preventing conduction of the nervous tissue after cessation of delivering of the first direct current. The nervous tissue can be maintained in the hypersuppressed state for a desired period, such as at least about 1 minute.

What is claimed is: 
     
       1. A system for nerve block of a patient utilizing a renewable electrode, comprising:
 a direct current generator; 
 at least one electrode comprising silver chloride, the at least one electrode configured to be in electrical communication with the direct current generator; 
 a controller configured to signal the direct current generator to:
 deliver a first direct current with a first polarity through the at least one electrode sufficient to block conduction in a nerve, decrease an amount of the silver chloride in the at least one electrode thereby forming solid silver and chloride ions; and 
 deliver a second direct current with a second polarity through the at least one electrode sufficient to increase the amount of the silver chloride, thereby renewing the at least one electrode; and 
 
 a nerve interface spaced apart from the at least one electrode by a selective barrier, the selective barrier configured to allow chloride ions through the barrier toward the nerve interface to block the nerve. 
 
     
     
       2. The system of  claim 1 , further comprising a sensor configured to determine whether a predominantly silver/silver chloride reaction is occurring, and wherein the controller is further configured to receive data from the sensor and discontinue at least one of the first direct current signal or the second direct current signal when water is being electrolyzed. 
     
     
       3. The system of  claim 1 , wherein the selective barrier is further configured to prevent silver ions from passing through the barrier toward the nerve interface. 
     
     
       4. The system of  claim 1 , wherein the at least one electrode is housed in an insulated enclosure. 
     
     
       5. The system of  claim 1 , wherein the selective barrier comprises an ion exchange membrane. 
     
     
       6. The system of  claim 1 , wherein the selective barrier comprises a hydrogel. 
     
     
       7. The system of  claim 1 , wherein the system is devoid of any mechanically moving parts. 
     
     
       8. The system of  claim 1 , wherein the controller is configured to deliver the first direct current such that the amount of silver chloride decreased is greater than an amount capable of evenly covering a surface area of the at least one electrode prior to delivery of the first direct current. 
     
     
       9. A system for nerve block of a patient utilizing a renewable electrode, comprising:
 a direct current generator; 
 at least one implantable electrode comprising a solid component, an ionic component, and a nerve interface directly adjacent the ionic component, the at least one implantable electrode configured to be in electrical communication with the direct current generator; and 
 a controller configured to signal the direct current generator to:
 deliver a first direct current with a first polarity through the at least one implantable electrode sufficient to block conduction in a nerve and decrease an amount of the solid component; and 
 deliver a second direct current with a second polarity through the at least one implantable electrode sufficient to increase the amount of the solid component, thereby renewing the at least one implantable electrode. 
 
 
     
     
       10. The system of  claim 9 , further comprising a sensor configured to determine whether a predominantly solid component/ionic component reaction is occurring, wherein the controller is further configured to receive data from the sensor and discontinue at least one of the first direct current signal or the second direct current signal when water is being electrolyzed. 
     
     
       11. The system of  claim 9 , wherein the at least one implantable electrode is housed in an insulated enclosure. 
     
     
       12. The system of  claim 9 , wherein the at least one implantable electrode further comprises a layer spaced between the ionic component and the nerve, the layer configured to selectively allow negatively charged ions of the ionic component to pass through the layer and toward the nerve, and prevent positively charged ions of the ionic component from passing through the layer toward the nerve. 
     
     
       13. The system of  claim 9 , wherein the system is devoid of any mechanically moving parts. 
     
     
       14. The system of  claim 9 , wherein the nerve interface spaced apart from the at least one electrode by one or more selected from the group consisting of: a gel, a hydrogel, and an ion conductive polymer. 
     
     
       15. The system of  claim 9 , wherein the at least one implantable electrode is at least partially surrounded by an electrolyte solution. 
     
     
       16. The system of  claim 9 , wherein the solid component comprises silver, and the ionic component comprises silver chloride. 
     
     
       17. The system of  claim 9 , wherein the controller is configured to deliver the first direct current such that the amount of solid component decreased is greater than a surface area of the solid component. 
     
     
       18. The system of  claim 9 , wherein the controller is configured to maintain the nerve in a hypersuppressed state at least partially preventing conduction of the nerve for at least about 10 minutes after cessation of delivering of the first direct current. 
     
     
       19. A method for nerve block of a patient utilizing a renewable electrode, comprising:
 delivering a first direct current of a first polarity through an implanted electrode comprising a first component proximate a nerve sufficient to block conduction in the nerve; and 
 delivering a second direct current of a second polarity opposite the first polarity through the implanted electrode; 
 wherein the first direct current decreases an amount of the first component of the implanted electrode thereby producing a second component different from the first component; 
 wherein the second direct current increases the amount of the first component of the implanted electrode and decreases the amount of the second component to renew the implanted electrode. 
 
     
     
       20. The method of  claim 19 , further comprising dynamically sensing the amount of the first component or the second component in the implanted electrode while delivering the first direct current; and ceasing delivery of the first direct current when the amount of the first component or the second component is sensed to reach a pre-determined threshold value. 
     
     
       21. A method for nerve block of a patient utilizing a renewable electrode, comprising:
 delivering a first direct current of a first polarity through an electrode comprising a first component proximate a nerve sufficient to block conduction in the nerve, wherein the first direct current decreases an amount of the first component of the electrode thereby producing a second component different from the first component; 
 delivering a second direct current of a second polarity opposite the first polarity through the electrode, wherein the second direct current increases the amount of the first component of the electrode and decreases the amount of the second component to renew the electrode; and 
 dynamically sensing the amount of the first component or the second component in the electrode while delivering the first direct current; and ceasing delivery of the first direct current when the amount of the first component or the second component is sensed to reach a pre-determined threshold value.